#!/bin/sh

# START
set -e

# VARIABLES
PROGNAME=$(basename $0)
CONFIG=($HOME/.maza/)
HOST_FILE=(/etc/hosts)
COLOR_RED=`tput setaf 1`
COLOR_GREEN=`tput setaf 2`
COLOR_RESET=`tput sgr0`
LIST="list"
START_TAG="## MAZA - List ad blocking"
PROJECT="### https://github.com/tanrax/maza-ad-blocking"
AUTHOR="### Created by Andros Fenollosa (https://programadorwebvalencia.com/)"
END_TAG="## END MAZA"

# FUNCTIONS

## HELP
usage() {
    if [ "$*" != "" ] ; then
        echo "Error: $*"
    fi

    cat << EOF
Usage: $PROGNAME [OPTION]
Simple and efficient local ad blocking throughout the network.

Options:
status       Check if it's active or not
update       Update the list of DNS to be blocked
start        Activate blocking DNS.
stop         Stop blocking DNS.
--help       Display this usage message and exit
EOF

    exit 1
}

status() {
    if grep -qF "$START_TAG" "$HOST_FILE";then
        echo "${COLOR_GREEN}ENABLED${COLOR_RESET}"
    else
        echo "${COLOR_RED}DISABLED${COLOR_RESET}"
    fi
}

update() {
    # Make conf folder
    rm -f $CONFIG/$LIST
    mkdir -p $CONFIG
    # Download DNS list
    curl -L -s "https://pgl.yoyo.org/adservers/serverlist.php?showintro=0;hostformat=hosts" -o "$CONFIG/$LIST"
    # Clear list
    ## Get PRE tag
    sed -i .bak -n "/<pre>/,/<\/pre>/p" "$CONFIG/$LIST"
    ## Remove comments
    sed -i .bak '/^#/ d' "$CONFIG/$LIST"
    ## Remove first line
    sed -i .bak '1d' "$CONFIG/$LIST"
    ## Remove last line
    sed -i .bak '$ d' "$CONFIG/$LIST"
    ## Add start tag DNS list in first line
    sed -i .bak "1i\\
        $AUTHOR
        " "$CONFIG/$LIST"
    sed -i .bak "1i\\
        $PROJECT
        " "$CONFIG/$LIST"
    sed -i .bak "1i\\
        $START_TAG
        " "$CONFIG/$LIST"
    # Remove temp file
    rm "$CONFIG$LIST.bak"
    ## Add end tag DNS list in first line
    echo $END_TAG >> "$CONFIG/$LIST"
    # Notify user
    echo "${COLOR_GREEN}Done!${COLOR_RESET}"
}

start() {
    # Add List to host file
    cat "$CONFIG/$LIST" >> "$HOST_FILE"
    # Notify user
    echo "${COLOR_GREEN}ENABLED!${COLOR_RESET}"
}

stop() {
    # Remove list to host file
    sed -i -n "/$START_TAG/,/$END_TAG/d" "$HOST_FILE"

    # Remove temp file
    #rm "$HOST_FILE.bak"

    # Notify user
    echo "${COLOR_GREEN}DISABLED!${COLOR_RESET}"
}

# CONTROLE ARGUMENTS
isArg=""

while [ $# -gt 0 ] ; do
    case "$1" in
    --help)
        usage
        ;;
    status)
        isArg="1"
        status
        ;;
    update)
        isArg="1"
        update
        ;;
    start)
        isArg="1"
        start
        ;;
    stop)
        isArg="1"
        stop
        ;;
    *)
    esac
    shift
done

if [ -z $isArg ] ; then
    usage "Not enough arguments"
fi